The present teachings are predicated upon providing an improved parking brake for use in an existing disc brake system for use with vehicles. For example, the disc brake system may be used with almost any vehicle (e.g. car, truck, bus, train, airplane, or the like). Alternatively, the disc brake system may be integrated into assemblies used for manufacturing or other equipment that require a brake such as a lathe, winder for paper products or cloth, amusement park rides, wind turbines, or the like. However, the present teachings are most suitable for use with a passenger vehicle (e.g., a car, truck, sports utility vehicle, or the like).
Generally, a braking system includes a rotor, a caliper body, a support bracket, an inboard brake pad, and an outboard brake pad that are on opposing sides of the rotor. The caliper body further includes one or more fingers (with or without a piston), one or more piston bores, and a bridge that connects the one or more fingers to the piston bores or two opposing piston bores together. The piston bores each house a piston. The piston bores each have a bore axis that the pistons move along during a brake apply and a brake retract. The piston bores each include a fluid inlet, a closed wall, a front opening, and a cylindrical side wall that includes a seal groove located near the front opening. Typically, the fluid inlet is located in the closed wall of the piston bore so that when pressure is applied the fluid will flow into the piston bore. During a pressure apply the fluid will push the piston axially towards the front opening and into contact with a brake pad that generally includes a pressure plate and friction material and the friction material will contact the rotor on one side and an opposing brake pad will contact the rotor on an opposing side creating friction to stop rotation of the rotor and any component connected to the brake system. The brake pads may slide on an abutment along an axis of the pistons or the brake pads may include holes that receive pins and the brake pads may slide on pins that extend through the brake system so that a friction force may be created.
In these non-braking conditions when the vehicle is parked a parking brake may be used to prevent movement of the vehicle. The parking brake may be a discrete braking system or may use one or more components of a primary braking system. Parking brake systems typically include one or more brake pads and/or brake shoes that may be moved to create a parking force so that the vehicle is restrained during non-movement of a vehicle. These parking brake systems may be actuated by a cable that when moved biases a device that simultaneously actuates the brake pads and/or brake shoes to generate the parking force.
Examples of braking systems and associated parking brake systems are disclosed in U.S. Pat. Nos. 5,148,894; 5,769,189; 6,098,763; 6,139,460; 7,188,710; and U.S. International Application Publication No. WO2013/121395 all of which are expressly incorporated herein by reference for all purposes. It would be attractive to have a parking brake system that may be used with a fixed caliper, a floating caliper, or both. It would be attractive to have a parking brake system that may be used with a multi piston system to actuate the multiple pistons to create a parking brake force. What is needed is a parking brake system that utilizes existing brake components to create a braking force when the brake is at rest. What is needed is a brake system that evenly applies a braking force between multiple pistons of a brake component so that braking force is equally distributed along the brake component.